The hair was standing on our backs

This beauty was uttered on National Public Radio’s 99 Percent Invisible by Janet Marie Smith, an Orioles design director when Oriole Park at Camden Yards opened.  She was talking about how nervous they were on opening day.  This is a nice mash up of “hair standing on end” and “getting our backs up” (to make angry).  Perhaps she was thinking of someone with a hairy back?  This malaphor is heard on Episode 262 air date 6/13/17.  A big thanks to Erin Powers who heard this one and passed it on!
http://99percentinvisible.org/episode/in-the-same-ballpark/#playlist